Akai GX-221D User Manual

€020)
AT/NG
GROUNDS
| Mode
ransis- . |
tor |TRO201/ TRO202
TRO203/FRO401
TR204 |
|
| Normal | orp | oN | OFF OFF | OFF
B. 1
Ree | on | orF | on | on | oN
Chart 1
4, SYSTEM CONTROL CIRCUIT OPERATION
1) Tension Relay Operation
The tension relay functions to switch the supply
voltage only when the main motor is first started
or at reverse time when the starting torque changes
until stability is obtained. The tension relay also
prevents strong tension from being applied to the
tape when tape direction is changed by supplying
uniform voltage to both torque motors.
2) Mute Relay Operation
Because tape travel is show when the machine is
first switched to or from Forward and Reverse, the
mute relay mutes the line output signal until
proper main motor revolutions are reached.
3) System Controi Operation
In Schematic 1, at Forward Playback time,
because transistor TRO202 base bias is high when
compared with transistor TRO201, TRO202 is held
at ON condition. Consequently, the collector
_ voltage of TRO202 is low, and transistor TRO203
is OFF, Also because the condenser C0202 is
charged by the collector voltage of transistor
TRO201, the base bias of transistor TRO401 as
well as TR204 is low and is held at OFF condition.
When the Reverse Button is depressed, or the
sensing tape passes the reverse sensing pole, the
base of transistor TRO202 is grounded, the collec-
tor voltage of TRO202 increases and TRO203 is
turned ON, and because Rev. Relay RLO201
_ operates, main motor reverse revolutions begin.
REVRSE
PLUNGER SOLENOID
B.S,
9p.c, 24V
TR204 MUTE RELAY
RL206
Schematic 1
Also because of the TRO202 collector voltage
increase, the charge cument which has passed
diode
DO204
as
well
as
resistors
RO401
and
R218
and also the internal impedance of transistors
TRO401 and TR204 flows to condenser C0205,
and while this current is flowing, TRO401 and
TR204 is mdfintained at ON condition, and
Tension Relay RLO401 as well as Mute Relay
RL201 operates. :
When the main motor begins reverse revolutions
and proper tape speed is reached, the charge of
condenser C0205 will be stopped, TRO401 and
TR204 base bias will disappear and these two
transistors are turned off, the tension relay as well
as the Mute Relay is turned off, and proper reverse
mode operation begins. During reverse playback
when the FWD Button is depressed or the sensing
tape passes the FWD sensing pole, the base of
transistor TRO201 is grounded, TRO201 is turned
off and the collector voltage increases.
Accordingly, transistor TRO202 base bias becomes
high, TRO202 is turned ON and the collector
voltage decreases, At this time, TRO203 is turned
OFF, and Rev, Relay RLO201 is also turned OFF.
Thus, main motor revolutions are switched to
normal playback direction, Also because of the
TRO201 collector voltage increase, as at reverse
time, charge current flows to condenser C0202,
and transistor TRO401 and TR204 are turned ON.
Consequently, Tension Relay RLO401 as well as
Mute Relay RL201 operates. The main motor
begins forward revolutions and when proper tape
speed is reached, condenser C0202 charge will be
stopped, the Tension Relay as well as Mute Relay
is turned OFF, and proper forward mode opera-
tion begins.
At Stop or Recording mode, voltage is supplied to
TRO202 base, and because Reverse Button and
sensing tape is irrelevant, main motor revolutions
are always in forward playback direction.
i
13

Akai GX-221D Specifications

General

Brand	Akai
Model	GX-221D
Category	Tape Deck
Language	English